Integrated Power Unit Breather Relocation for Water Ingress Prevention
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Solution Overview
Problem
Existing integrated power electric units in electric vehicles are prone to water ingress through breathers when submerged, as the pressure difference between the inside and outside of the casings can cause water to rush in, especially when the motor casing is positioned lower than the inverter casing.
Innovation Solution
An integrated power electric unit is designed with a channel connecting the motor and inverter casings, and a breather is provided in the higher-mounted power distribution module (PDM) casing, allowing air to communicate between the inside and outside, equalizing internal pressure with atmospheric pressure and preventing water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If breathers are provided in both motor casing and inverter casing, then air communication is improved, but water ingress risk increases when motor casing is submerged
Solution Approach 1:
The breather is extracted from the motor casing and relocated to the inverter casing, which is positioned higher. This removes the harmful element (breather in submerged position) while preserving the useful function (air communication) through the channel system connecting motor and inverter casings.
Solution Approach 2:
The solution moves the breather from a lower vertical dimension (motor casing) to a higher vertical dimension (inverter casing). By changing the vertical position to the highest point, the system prevents water ingress while maintaining air communication through the channel network.
2Reliability
If multiple breathers are provided in different casings, then pressure equalization is improved, but device complexity increases
Solution Approach 1:
Multiple breather functions are merged into a single breather located in the inverter casing. The channel system connecting motor and inverter casings allows one breather to perform the pressure equalization function for the entire integrated unit, reducing component count while maintaining reliability.
3Ease of operation
If breathers are provided in lower-positioned casings, then air communication is improved, but water rush risk increases during submersion
Solution Approach 1:
The breather is repositioned from the lower vertical dimension to the highest vertical dimension in the system. This dimensional change ensures that during submersion, the breather remains above water level while still enabling air communication through the channel system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents water from entering the unit during submersion by equalizing internal and external pressures, reduces costs by using a single breather, and simplifies air leakage inspection, while also minimizing contamination and splash risks.
Implementation Method 1
a breather provided in the second power electric unit to cause inner and outer sides of the second power electric unit to communicate with each other
Data Source
Figure 1
Figure 2
AI summary
Disclosed is an integrated power electric unit mounted on an electric vehicle, comprising a first power electric unit, a second power electric unit arranged over the first power electric unit in a vertical direction of the vehicle, a channel that connects the first and second power electric units so as to flow the air, and a breather provided in the second power electric unit to cause inner and outer sides of the second power electric unit to communicate with each other.